Showing papers in "Materials futures in 2022"

Deep Potentials for Materials Science

Abstract: To fill the gap between accurate (and expensive) ab initio calculations and efficient atomistic simulations based on empirical interatomic potentials, a new class of descriptions of atomic interactions has emerged and been widely applied; i.e., machine learning potentials (MLPs). One recently developed type of MLP is the Deep Potential (DP) method. In this review, we provide an introduction to DP methods in computational materials science. The theory underlying the DP method is presented along with a step-by-step introduction to their development and use. We also review materials applications of DPs in a wide range of materials systems. The DP Library provides a platform for the development of DPs and a database of extant DPs. We discuss the accuracy and efficiency of DPs compared with ab initio methods and empirical potentials.

Interface and surface engineering of black phosphorus: a review for photonic and optoelectronic applications

Abstract: Since being rediscovered as an emerging 2D material, BP with extraordinary energy structure and unusually strong interlayer interactions offer new opportunities for optoelectronics and photonics. However, due to the thin atomic body and the ease of degradation with water and oxides, BP is highly sensitive to the surrounding environment. Therefore, high-quality engineering of interfaces and surfaces plays an essential role in BP-based applications. In this review, begun with a review of properties of BP, different strategies of interface and surfaces engineering for high ON-OFF ratio, enhanced optical absorption, and fast optical response are reviewed and highlighted, and recent state-of-the-art advances on optoelectronic and photonic devices are demonstrated. Finally, the opportunities and challenges are outlooked for future BP-related research.

Multiscale understanding of high-energy cathodes in solid-state batteries: from atomic scale to macroscopic scale

Abstract: Abstract In the crucial area of sustainable energy storage, solid-state batteries (SSBs) with nonflammable solid electrolytes stand out due to their potential benefits of enhanced safety, energy density, and cycle life. However, the complexity within the composite cathode determines that fabricating an ideal electrode needs to link chemistry (atomic scale), materials (microscopic/mesoscopic scale), and electrode system (macroscopic scale). Therefore, understanding solid-state composite cathodes covering multiple scales is of vital importance for the development of practical SSBs. In this review, the challenges and basic knowledge of composite cathodes from the atomic scale to the macroscopic scale in SSBs are outlined with a special focus on the interfacial structure, charge transport, and mechanical degradation. Based on these dilemmas, emerging strategies to design a high-performance composite cathode and advanced characterization techniques are summarized. Moreover, future perspectives toward composite cathodes are discussed, aiming to facilitate the develop energy-dense SSBs.

Recent advances and future perspectives for aqueous zinc-ion capacitors

Abstract: Abstract Ion-hybrid capacitors are expected to combine the high specific energy of battery-type materials and the superior specific power of capacitor-type materials and are considered as a promising energy storage technique. In particular, aqueous zinc-ion capacitors (ZIC), possessing the merits of high safety, cost-efficiency and eco-friendliness, have been widely explored with various electrode materials and electrolytes to obtain excellent electrochemical performance. In this review, we first summarize the research progress on enhancing the specific capacitance of capacitor-type materials and review the research on improving the cycling capability of battery-type materials under high current densities. Then, we look back on the effects of electrolyte engineering on the electrochemical performance of ZIC. Finally, we propose research challenges and development directions for ZIC. This review provides guidance for the design and construction of high-performance ZIC.

Air exposure towards stable Li/Li10GeP2S12 interface for all-solid-state lithium batteries

Abstract: Moist air is a great challenge for manufacturing sulfide-based all-solid-state lithium batteries as the water in air will lead to severe decomposition of sulfide electrolytes and release H2S gas. However, different with direct reaction with water, short-period air exposure of Li10GeP2S12 sulfide electrolyte with controlled humidity can greatly enhance the stability of Li10GeP2S12 against lithium metal, thus realizing stable Li10GeP2S12 based all-solid-state lithium metal batteries. During air exposure, partial hydrolysis reaction occurs on the surface of Li10GeP2S12 pellets, rapidly generating a protective decomposition layer of Li4P2S6, GeS2 and Li2HPO3 in dozens of seconds. This ionically conductive but electronically insulation protecting layer can effectively prevent the severe interface reaction between Li10GeP2S12 and lithium metal during electrochemical cycling. The Li/40s-air-exposed Li10GeP2S12/Li cell shows long cycling stability for 1000 h. And the LiCoO2/40s-air-exposed Li10GeP2S12/Li batteries present good rate capability and long cyclic performances, showing capacity retention of 80% after 100 cycles.

Defect passivation and electrical conductivity enhancement in perovskite solar cells using functionalized graphene quantum dots

Abstract: Organic–inorganic halide perovskites have been intensively investigated as potential photovoltaic materials due to their exceptional optoelectronic properties and their successful applications in perovskite solar cells (PSCs). However, a large number of defect states still exist in the PSCs so far and are detrimental to their power conversion efficiencies (PCEs) and stability. Here, an effective strategy of incorporating single-crystalline graphene quantum dots (GQDs) into the perovskite films is proposed to passivate the defect states. Intriguingly, the GQD-modified perovskite films exhibit purer phase structure, higher quality of morphology, and higher electrical conductivity when compared with the control perovskite films. All of the advantages caused by the incorporation of the GQDs lead to fast carrier separation and transport, long carrier lifetime, and low nonradiative recombination in the PSCs based on the GQD-modified perovskite films. As a result, this kind of PSC displays an increase in all photovoltaic parameters, and its PCE shows an enhancement of more than 20% when compared with the control PSC. Moreover, this novel PSC is demonstrated to have long-term stability and resistibility against heat and moisture. Our findings provide an insight into how to passivate the defect states and enhance the electrical conductivities in the perovskites and pave the way for their further exploration to achieve higher photovoltaic performances.

P2-type layered high-entropy oxides as sodium-ion cathode materials

Abstract: P2-type layered oxides with the general Na-deficient composition Na x TMO2 (x < 1, TM: transition metal) are a promising class of cathode materials for sodium-ion batteries. The open Na+ transport pathways present in the structure lead to low diffusion barriers and enable high charge/discharge rates. However, a phase transition from P2 to O2 structure occurring above 4.2 V and metal dissolution at low potentials upon discharge results in rapid capacity degradation. In this work, we demonstrate the positive effect of configurational entropy on the stability of the crystal structure during battery operation. Three different compositions of layered P2-type oxides were synthesized by solid-state chemistry, Na0.67(Mn0.55Ni0.21Co0.24)O2, Na0.67(Mn0.45Ni0.18Co0.24Ti0.1Mg0.03)O2 and Na0.67(Mn0.45Ni0.18Co0.18Ti0.1Mg0.03Al0.04Fe0.02)O2 with low, medium and high configurational entropy, respectively. The high-entropy cathode material shows lower structural transformation and Mn dissolution upon cycling in a wide voltage range from 1.5 to 4.6 V. Advanced operando techniques and post-mortem analysis were used to probe the underlying reaction mechanism thoroughly. Overall, the high-entropy strategy is a promising route for improving the electrochemical performance of P2 layered oxide cathodes for advanced sodium-ion battery applications.

Field-free approaches for deterministic spin-orbit torque switching of the perpendicular magnet

Abstract: All-electrical driven magnetization switching attracts much attention in next-generation spintronic memory and logic devices, particularly in magnetic random-access memory (MRAM) based on the spin-orbit torque (SOT), i.e., SOT-MRAM, due to its advantages of low power consumption, fast write/read speed, and improved endurance, etc. For conventional SOT-driven switching of the magnet with perpendicular magnetic anisotropy (PMA), an external assisted magnetic field is needed to break the inversion symmetry of the magnet, which not only induces the additional power consumption but also makes the circuit more complicated. Over the last decade, significant effort has been devoted to field-free magnetization manipulation by using SOT. In this review, we introduce the basic concepts of SOT. After that, we mainly focus on several approaches to realize the field-free deterministic SOT switching of the perpendicular magnet. The mechanisms mainly include mirror symmetry breaking, chiral symmetry breaking, exchange bias, and interlayer exchange coupling. Furthermore, we show the recent progress on the study of SOT with unconventional origin and symmetry. The final section is devoted to the industrial-level approach for potential applications of field-free SOT switching in SOT-MRAM technology.

Bilayer metal halide perovskite for efficient and stable solar cells and modules

Abstract: To reach the target of carbon neutral, a transition from fossil energy to renewable energy is unavoidable. Photovoltaic technology is considered one of the most prominent sources of renewable energy. Recently, metal halide perovskite materials have attracted tremendous interest in the areas of optoelectronic devices due to their ease of processing and outstanding performance. To date, perovskite solar cells (PSCs) have shown high power conversion efficiency up to 25.7% and 31.3% for the perovskite-silicon tandem solar cells, which promises to revolutionize the PV landscape. However, the stability of PSCs under operating conditions has yet to match state-of-the-art silicon-based solar cell technology, in which the stability of the absorbing layer and relevant interfaces is the primary challenge. These issues become more serious in the larger area solar modules due to the additional interfaces and more defects within the perovskite. Bilayer perovskite film composed of a thin low dimensional perovskite layer and a three-dimensional perovskite layer shows great potential in fabricating solar cells with high efficiency and stability simultaneously. In this review, recent advancements, including composition design and processing methods for constructing bilayer perovskite films are discussed. We then analyze the challenges and resolutions in deposition bilayer perovskite films with scalable techniques. After summarizing the beneficial effect of the bilayer structure, we propose our thinking of feasible strategies to fabricate high efficiency perovskite solar modules with a long lifetime. Finally, we outline the directions for future work that will push the perovskite PV technology toward commercialization.

Ion transport and structural design of lithium-ion conductive solid polymer electrolytes: a perspective

Abstract: Solid polymer electrolytes (SPEs) possess several merits including no leakage, ease in process, and suppressing lithium dendrites growth. These features are beneficial for improving the cycle life and safety performance of rechargeable lithium metal batteries (LMBs), as compared to conventional non-aqueous liquid electrolytes. Particularly, the superior elasticity of polymeric material enables the employment of SPEs in building ultra-thin and flexible batteries, which could further expand the application scenarios of high-energy rechargeable LMBs. In this perspective, recent progresses on ion transport mechanism of SPEs and structural designs of electrolyte components (e.g. conductive lithium salts, polymer matrices) are scrutinized. In addition, key achievements in the field of single lithium-ion conductive SPEs are also outlined, aiming to provide the status quo in those SPEs with high selectivity in cationic transport. Finally, possible strategies for improving the performance of SPEs and their rechargeable LMBs are also discussed.

Recent development of chemically complex metallic glasses: from accelerated compositional design, additive manufacturing to novel applications

Abstract: Abstract Metallic glasses (MGs) or amorphous alloys are an important engineering material that has a history of research of about 80–90 years. While different fast cooling methods were developed for multi-component MGs between 1960s and 1980s, 1990s witnessed a surge of research interest in the development of bulk metallic glasses (BGMs). Since then, one central theme of research in the metallic-glass community has been compositional design that aims to search for MGs with a better glass forming ability, a larger size and/or more interesting properties, which can hence meet the demands from more important applications. In this review article, we focus on the recent development of chemically complex MGs, such as high entropy MGs, with new tools that were not available or mature yet until recently, such as the state-of-the-art additive manufacturing technologies, high throughput materials design techniques and the methods for big data analyses (e.g. machine learning and artificial intelligence). We also discuss the recent use of MGs in a variety of novel and important applications, from personal healthcare, electric energy transfer to nuclear energy that plays a pivotal role in the battle against global warming.

On the role of surface carbonate species in determining the cycling performance of all-solid-state batteries

Abstract: This short perspective summarizes recent findings on the role of residual lithium present on the surface of layered Ni-rich oxide cathode materials in liquid- and solid-electrolyte based batteries, with emphasis placed on the carbonate species. Challenges and future research opportunities in the development of carbonate-containing protective nanocoatings for inorganic solid-state battery applications are also discussed.

Ultrafast Flash Memory with Large Self-Rectifying Ratio Based on Atomically Thin MoS2-Channel Transistor

Abstract: Flash memory with high operation speed and stable retention performance is in great demand to meet the requirements of big data. In addition, the realisation of ultrafast flash memory with novel functions offers a means of combining heterogeneous components into a homogeneous device without considering impedance matching. This report proposes a 20 ns programme flash memory with 108 self-rectifying ratios based on a 0.65-nm-thick MoS2-channel transistor. A high-quality van der Waals heterojunction with a sharp interface is formed between the Cr/Au metal floating layer and h-BN tunnelling layer. In addition, the large rectification ratio and low ideality factor (n = 1.13) facilitate the application of the MoS2-channel flash memory as a bit-line select transistor. Finally, owing to the ultralow MoS2/h-BN heterojunction capacitance (50 fF), the memory device exhibits superior performance as a high-frequency (up to 1 MHz) sine signal rectifier. These results pave the way toward the potential utilisation of multifunctional memory devices in ultrafast two-dimensional NAND-flash applications.

Reinforced cathode-garnet interface for high-capacity all-solid-state batteries

Abstract: Garnet-type solid-state electrolytes (SSEs) are particularly attractive in the construction of all-solid-state lithium (Li) batteries due to their high ionic conductivity, wide electrochemical window and remarkable (electro)chemical stability. However, the intractable issues of poor cathode/garnet interface and general low cathode loading hinder their practical application. Herein, we demonstrate the construction of a reinforced cathode/garnet interface by spark plasma sintering, via co-sintering Li6.5La3Zr1.5Ta0.5O12 (LLZTO) electrolyte powder and LiCoO2/LLZTO composite cathode powder directly into a dense dual-layer with 5 wt% Li3BO3 as sintering additive. The bulk composite cathode with LiCoO2/LLZTO cross-linked structure is firmly welded to the LLZTO layer, which optimizes both Li-ion and electron transport. Therefore, the one-step integrated sintering process implements an ultra-low cathode/garnet interfacial resistance of 3.9 Ω cm2 (100 °C) and a high cathode loading up to 2.02 mAh cm−2. Moreover, the Li3BO3 reinforced LiCoO2/LLZTO interface also effectively mitigates the strain/stress of LiCoO2, which facilitates the achieving of superior cycling stability. The bulk-type Li|LLZTO|LiCoO2-LLZTO full cell with areal capacity of 0.73 mAh cm−2 delivers capacity retention of 81.7% after 50 cycles at 100 μA cm−2. Furthermore, we reveal that non-uniform Li plating/stripping leads to the formation of gaps and finally results in the separation of Li and LLZTO electrolyte during long-term cycling, which becomes the dominant capacity decay mechanism in high-capacity full cells. This work provides insight into the degradation of Li/SSE interface and a strategy to radically improve the electrochemical performance of garnet-based all-solid-state Li batteries.

A self-assembled nanoflower-like Ni5P4@NiSe2 heterostructure with hierarchical pores triggering high-efficiency electrocatalysis for Li–O2 batteries

Abstract: The remarkably high theoretical energy densities of Li–O2 batteries have triggered tremendous efforts for next-generation conversion devices. Discovering efficient oxygen reduction reaction and oxygen evolution reaction (ORR/OER) bifunctional catalysts and revealing their internal structure-property relationships are crucial in developing high-performance Li–O2 batteries. Herein, we have prepared a nanoflower-like Ni5P4@NiSe2 heterostructure and employed it as a cathode catalyst for Li–O2 batteries. As expected, the three-dimensional biphasic Ni5P4@NiSe2 nanoflowers facilitated the exposure of adequate active moieties and provide sufficient space to store more discharge products. Moreover, the strong electron redistribution between Ni5P4 and NiSe2 heterojunctions could result in the built-in electric fields, thus greatly facilitating the ORR/OER kinetics. Based on the above merits, the Ni5P4@NiSe2 heterostructure catalyst improved the catalytic performance of Li–O2 batteries and holds great promise in realizing their practical applications as well as inspiration for the design of other catalytic materials.

Scanning probe microscopy in probing low-dimensional carbon-based nanostructures and nanomaterials

Abstract: Carbon, as an indispensable chemical element on Earth, has diverse covalent bonding ability, which enables construction of extensive pivotal carbon-based structures in multiple scientific fields. The extraordinary physicochemical properties presented by pioneering synthetic carbon allotropes, typically including fullerenes, carbon nanotubes, and graphene, have stimulated broad interest in fabrication of carbon-based nanostructures and nanomaterials. Accurate regulation of topology, size, and shape, as well as controllably embedding target sp n -hybridized carbons in molecular skeletons, is significant for tailoring their structures and consequent properties and requires atomic precision in their preparation. Scanning probe microscopy (SPM), combined with on-surface synthesis strategy, has demonstrated its capabilities in fabrication of various carbon-based nanostructures and nanomaterials with atomic precision, which has long been elusive for conventional solution-phase synthesis due to realistic obstacles in solubility, isolation, purification, etc. More intriguingly, atom manipulation via an SPM tip allows unique access to local production of highly reactive carbon-based nanostructures. In addition, SPM provides topographic information of carbon-based nanostructures as well as their characteristic electronic structures with unprecedented submolecular resolution in real space. In this review, we overview recent exciting progress in the delicate application of SPM in probing low-dimensional carbon-based nanostructures and nanomaterials, which will open an avenue for the exploration and development of elusive and undiscovered carbon-based nanomaterials.

Advanced atomic force microscopies and their applications in two-dimensional materials: a review

Abstract: Scanning probe microscopy (SPM) allows the spatial imaging, measurement, and manipulation of nano and atomic scale surfaces in real space. In the last two decades, numerous advanced and functional SPM methods, particularly atomic force microscopy (AFM), have been developed and applied in various research fields, from mapping sample morphology to measuring physical properties. Herein, we review the recent progress in functional AFM methods and their applications in studies of two-dimensional (2D) materials, particularly their interfacial physical properties on the substrates. This review can inspire more exciting application works using advanced AFM modes in the 2D and functional materials fields.

Microfluidic 3D printing polyhydroxyalkanoates-based bionic skin for wound healing

Abstract: Abstract Biomimetic scaffolds with extracellular matrix (ECM)-mimicking structure have been widely investigated in wound healing applications, while insufficient mechanical strength and limited biological activity remain major challenges. Here, we present a microfluidic 3D printing biomimetic polyhydroxyalkanoates-based scaffold with excellent mechanical properties and hierarchical porous structures for enhanced wound healing. This scaffold is composed of poly(3-hydroxybutyrate-4-hydroxybutyrate) and polycaprolactone, endowing it with excellent tensile strength (2.99 MPa) and degradability (80% of weight loss within 7 d). The ECM-mimicking hierarchical porous structure allows bone marrow mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) to proliferate and adhere on the scaffolds. Besides, anisotropic composite scaffolds loaded with BMSCs and HUVECs can significantly promote re-epithelization, collagen deposition and capillary formation in rat wound defects, indicating their satisfactory in vivo tissue regenerative activity. These results indicate the feasibility of polyhydroxyalkanoates-based biomimetic scaffolds for skin repair and regeneration, which also provide a promising therapeutic strategy in diverse tissue engineering applications.

Biomaterials for microfluidic technology

Abstract: Abstract Micro/nanomaterial-based drug and cell delivery systems play an important role in biomedical fields for their injectability and targeting. Microfluidics is a rapidly developing technology and has become a robust tool for preparing biomaterial micro/nanocarriers with precise structural control and high reproducibility. By flexibly designing microfluidic channels and manipulating fluid behavior, various forms of biomaterial carriers can be fabricated using microfluidics, including microspheres, nanoparticles and microfibers. In this review, recent advances in biomaterials for designing functional microfluidic vehicles are summarized. We introduce the application of natural materials such as polysaccharides and proteins as well as synthetic polymers in the production of microfluidic carriers. How the material properties determine the manufacture of carriers and the type of cargoes to be encapsulated is highlighted. Furthermore, the current limitations of microfluidic biomaterial carriers and perspectives on its future developments are presented.

Properties and Processing Technologies of High-entropy Alloys

Abstract: High-entropy alloys (HEAs) are emerging materials that are developed based on entropy and draw significant attention for designing their chemical disorders to bring different structural and physical characteristics. Over the past two decades, significant salient efforts have been conducted to explore many unique and useful properties of HEAs, such as overcoming the strength-ductile trade off, outstanding thermal stability, and excellent low temperature plasticity. Here, we review the key research topic of HEAs from the following three aspects: (i) performance advantages and composition design, (ii) performance-driven HEAs and (iii) fabrication process-driven HEAs. Towards their industrial applications, our article reviews a large range of methods to synthesis, fabricate and process HEAs. We also discuss the current challenges and future opportunities, mainly focusing on performance breakthroughs in HEAs.

Unleashing energy storage ability of aqueous battery electrolytes

Abstract: Abstract Electrolytes make up a large portion of the volume of energy storage devices, but they often do not contribute to energy storage. The ability of using electrolytes to store charge would promise a significant increase in energy density to meet the needs of evolving electronic devices. Redox-flow batteries use electrolytes to store energy and show high energy densities, but the same design cannot be applied to portable or microdevices that require static electrolytes. Therefore, implementing electrolyte energy storage in a non-flow design becomes critical. This review summarizes the requirements for a stable and efficient electrolyte and diverse redox-active species dissolved in aqueous solutions. More importantly, we review the pioneering works using static electrolyte energy storage in the hope that it will pave a new way to design compact and energy-dense batteries.

Concentrated electrolytes for rechargeable lithium metal batteries

Abstract: Traditional lithium-ion batteries with graphite anodes have gradually been limited by the glass ceiling of energy density. As a result, lithium metal batteries (LMBs), regarded as the ideal alternative, have attracted considerable attention. However, lithium is highly reactive and susceptible to most electrolytes, resulting in poor cycle performance. In addition, lithium grows Li dendrites during charging, adversely affecting the safety of LMBs. Therefore, LMBs are more sensitive to the chemical composition of electrolytes and their relative ratios (concentrations). Recently, concentrated electrolytes have been widely demonstrated to be friendly to lithium metal anodes (LMAs). This review focuses on the progress of concentrated electrolytes in LMBs, including the solvation structure varying with concentration, unique functions in stabilizing the LMA, and their interfacial chemistry with LMA.

Inheritance factor on the physical properties in metallic glasses

Abstract: Material genetic engineering can significantly accelerate the development of new materials. As an important topic in material science and condensed matter physics, the development of metallic glasses (MGs) with specific properties has largely been the result of trial and error since their discovery in 1960. Yet, property design based on the physical parameters of constituent elements of MGs remains a huge challenge owing to the lack of an understanding of the property inheritance from constitute elements to the resultant alloys. In this work, we report the inherent relationships of the yield strength σ y, Young’s modulus E, and shear Modulus G with the valence electron density. More importantly, we reveal that the electronic density of states (EDOSs) at the Fermi surface (E F) is an inheritance factor for the physical properties of MGs. The physical properties of MGs are inherited from the specific element with the largest coefficient of electronic specific heat (γi ), which dominates the value of the EDOS at E F. This work not only contributes to the understanding of property inheritances but also guides the design of novel MGs with specific properties based on material genetic engineering.

Tunable metallic-like transport in polypyrrole

Abstract: Abstract Conjugated polymers (CPs), organic macromolecules with a linear backbone of alternating C–C and C=C bonds, possess unique semiconductive properties, providing new opportunities for organic electronics, photonics, information, and energy devices. Seeking the metallic or metallic-like, even superconducting properties beyond semiconductivity in CPs is always one of the ultimate goals in polymer science and condensed matter. Only two metallic and semi-metallic transport cases—aniline-derived polyaniline and thiophene-derived poly(3,4-ethylenedioxythiophene)—have been reported since the development of CPs for four decades. Controllable synthesis is a key challenge in discovering more cases. Here we report the metallic-like transport behavior of another CP, polypyrrole (PPy). We observe that the transport behavior of PPy changes from semiconductor to insulator-metal transition, and gradually realizes metallic-like performance when the crystalline degree increases. Using a generalized Einstein relation model, we rationalized the mechanism behind the observation. The metallic-like transport in PPy demonstrates electron strong correlation and phonon–electron interaction in soft condensation matter, and may find practical applications of CPs in electrics and spintronics.

Investigating inexpensive polymeric 3D printed materials under extreme thermal conditions

Abstract: Abstract 3D printing is nowadays used for many applications far beyond pure rapid prototyping. As tools to prepare custom-made objects which may be highly complex, different 3D printing techniques have emerged into areas of application where the mechanical, thermal, optical and other properties have to meet high requirements. Amongst them, applications for space, e.g. for microsatellites, make extreme demands regarding the stability under high temperatures. Nevertheless, polymeric 3D printed materials have several advantages for space application in comparison with metal objects. Here we thus investigate the impact of temperatures up to 85 °C and 185 °C, respectively, on typical 3D printing materials for fused deposition modeling or stereolithography (SLA) with inexpensive 3D printers. The materials are found to differ strongly in terms of mechanical properties and dimensional stability after the treatment at a higher temperature, with SLA resins and co-polyester showing the best dimensional stability, while acrylonitrile–butadiene–styrene and SLA resin after long UV post-treatment has the best mechanical properties.

Low Na-β′′-alumina electrolyte/cathode interfacial resistance enabled by a hydroborate electrolyte opening up new cell architecture designs for all-solid-state sodium batteries

Abstract: Development of low-resistance electrode/electrolyte interfaces is key for enabling all-solid-state batteries with fast-charging capabilities. Low interfacial resistance and high current density were demonstrated for Na-β′′-alumina/sodium metal interfaces, making Na-β′′-alumina a promising solid electrolyte for high-energy all-solid-state batteries. However, integration of Na-β′′-alumina with a high-energy sodium-ion intercalation cathode remains challenging. Here, we report a proof-of-concept study that targets the implementation of a Na-β′′-alumina ceramic electrolyte with a slurry-casted porous NaCrO2 cathode with infiltrated sodium hydroborates as secondary electrolyte. The hydroborate Na4(B12H12)(B10H10) possesses similar sodium-ion conductivity of 1 mS cm−1 at room temperature as Na-β′′-alumina and can be fully densified by cold pressing. Using the Na4(B12H12)(B10H10) secondary electrolyte as interlayer between Na-β′′-alumina and NaCrO2, we obtain a cathode-electrolyte interfacial resistance of only 25 Ω cm2 after cold pressing at 70 MPa. Proof-of-concept cells with a sodium metal anode and a NaCrO2 cathode feature an initial discharge capacity of 103 mAh g−1 at C/10 and 42 mAh g−1 at 1 C with an excellent capacity retention of 88% after 100 cycles at 1 C at room temperature. Ion-milled cross-sections of the cathode/electrolyte interface demonstrate that intimate contact is maintained during cycling, proving that the use of hydroborates as secondary electrolyte and as an interlayer is a promising approach for the development of all-solid-state batteries with ceramic electrolytes.

Microstructure and long-term stability of Ni–YSZ anode supported fuel cells: a review

Abstract: Nickel–yttria stabilized zirconia (Ni–YSZ) cermet is the most commonly used anode in solid oxide fuel cells (SOFCs). The current article provides an insight into parameters which affect cell performance and stability by reviewing and discussing the related publications in this field. Understanding the parameters which affect the microstructure of Ni–YSZ such as grain size (Leng et al 2003 J. Power Sources 117 26–34) and ratio of Ni to YSZ, volume fraction of porosity, pore size and its distribution, tortuosity factor, characteristic pathway diameter and density of triple phase boundaries is the key to designing a fuel cell which shows high electrochemical performance. Lack of stability has been the main barrier to commercialization of SOFC technology. Parameters influencing the degradation of Ni–YSZ supported SOFCs such as Ni migration inside the anode during prolonged operation are discussed. The longest Ni-supported SOFC tests reported so far are examined and the crucial role of chromium poisoning due to interconnects, stack design and operating conditions in degradation of SOFCs is highlighted. The importance of calcination and milling of YSZ to development of porous structures suitable for Ni infiltration is explained and several methods to improve the electrochemical performance and stability of Ni–YSZ anode supported SOFCs are suggested.

All-solid-state thin-film batteries based on lithium phosphorus oxynitrides

Abstract: Lithium phosphorus oxygen nitrogen (LiPON) as solid electrolyte discovered by Bates et al in the 1990s is an important part of all-solid-state thin-film battery (ASSTFB) due to its wide electrochemical stability window and negligible low electronic conductivity. However, the ionic conductivity of LiPON about 2 × 10−6 S cm−1 at room temperature is much lower than that of other types of solid electrolytes, which seriously limits the application of ASSTFBs. This review summarizes the research and progress in ASSTFBs based on LiPON, in the solid-state electrolyte of LiPON-derivatives with adjustable chemical compositions of the amorphous structure for the improvement of the ionic conductivity and electrochemical stability, in the critical interface issues between LiPON and electrodes, and in preparation methods for LiPON. This review is helpful for people to understand the interface characteristics and various preparation methods of LiPON in ASSTFBs. The key issues to be addressed concern how to develop solid-state electrolyte films with high conductivity and high-quality interface engineering as well as large-scale preparation technology, so as to realize the practical application of highly integrated ASSTFBs.

Efficient nanozyme engineering for antibacterial therapy

Abstract: Antimicrobial resistance (AMR) has posed a huge threat to human health. It is urgent to explore efficient ways to suppress the spread of AMR. Antibacterial nanozymes has become one of the powerful weapons to combat AMR due to their enzyme-like catalytic activity with a broad-spectrum antibacterial performance. However, the inherent low catalytic activity of nanozymes limits their expansion into antibacterial applications. In this regard, a variety of advanced chemical design strategies have been developed to improve the antimicrobial activity of nanozymes. In this review, we have summarized the recent progress of advanced strategies to engineering efficient nanozymes for fighting against AMR, which can be mainly classified into catalytic activity improvement, external stimuli, bacterial affinity enhancement, and multifunctional platform construction according to the basic principles of engineering efficient nanocatalysts and the mechanism of nanozyme catalysis. Moreover, the deep insights into the effects of these enhancing strategies on the nanozyme structures and properties are highlighted. Finally, current challenges and future perspectives of antibacterial nanozymes are discussed for their future clinical potential.

Facile molten salt synthesis of carbon-anchored TiN nanoparticles for durable high-rate lithium-ion battery anodes

Abstract: Transition metal nitrides (TMNs), including titanium nitride (TiN), exhibit remarkable application prospects as anodes for durable high-rate lithium-ion batteries (LIBs). Regrettably, the absence of simple synthesis methods restricts their further development. Herein, a facile and low-cost molten salt synthesis strategy was proposed to prepare carbon-anchored TiN nanoparticles as an advanced anode material for LIBs with high rate capabilities. This nanosized TiN obtained is ∼5 nm in size and well-distributed onto carbon plates, which could release a reversible capacity of ∼381.5 mAh g−1 at 0.1 A g−1 after 250 cycles and ∼141.5 mAh g−1 at 1.0 A g−1 after 1000 cycles. Furthermore, it was confirmed that the conversion reaction between TiN and Li-ions happened during the electrochemical reaction process, resulting in the formation of Li3N and Ti. This unique microstructure attributed from TiN nanoparticles anchored by carbon could support the structural volume during cycling. This work highlights the method superiority of TiN prepared via a molten salt synthesis strategy as an anode for LIBs with impressive rate performances.